Static characteristics of the pneumatic power amplifier "nozzle-shutter"

Abstract

The results of an experimental study of the mechanic-pneumatic converter "nozzle-shutter" and the pneumatic power amplifier created on its basis are presented. Such devices can be used in the design of damping systems for a multi-bearing oscillatory system of a special-purpose vehicle intended for the transport of "delicate" goods. The algorithm for controlling the adaptive air-hydraulic spring is rather complicated and it may require expensive hydraulic equipment with electromagnetic proportional control for its implementation. A possible alternative to such equipment are pneumatic devices built on the basis of adjustable throttles "nozzle-shutter". The installation on board of vehicles on wheeled or caterpillar tracks of cargo beams or platforms with a load fixed to them may be associated with the need for their stabilization in a horizontal position in the case of a shift in the center of gravity of the cargo relative to the vertical axis. Such a problem can be solved using differential hydraulic cylinders with a cross-connection of their piston and rod cavities, and compensation for the difference in feed rates and costs should be ensured by means of pneumatic-hydraulic accumulators. In both cases, a pressure control system is required in the gas cavities of an air-hydraulic spring or an air-hydraulic accumulator, which can be implemented on the basis of a mechanic-pneumatic converter or a pneumatic power amplifier. In pneumatic continuous control systems used in mobile equipment, the directing and distribution subsystem is usually built on the basis of pneumatic throttling valves with electromagnetic proportional control. Due to the limited power of proportional electromagnets, the creation of such pneumatic directional valves is limited by their throughput. In the throttling pneumatic distributors of indirect action, the replacement of the power amplifier of the spool type with the power amplifier "nozzle-shutter" improves the dynamic characteristics of the distributor and reduces its cost. It is possible to use the obtained experimental flow-control, adjustment and power characteristics presented in dimensionless parameters when calculating the adaptive suspension of multi-axis transport systems and the cargo platforms stabilized on the horizon.